Module Name: src
Committed By: manu
Date: Wed Sep 21 15:36:33 UTC 2011
Modified Files:
src/sys/fs/puffs: puffs_vfsops.c puffs_vnops.c
Log Message:
Make sure ioflush does not sleep in PUFFS code path, waiting for a mutex,
a memory allocation, or a response from the filesystem.
This avoids deadlocks in the following situations:
1) when memory is low: ioflush waits the fileystem, the fielsystem waits
for memory
2) when the filesystem does not respond (e.g.: network outage ona
distributed filesystem)
To generate a diff of this commit:
cvs rdiff -u -r1.96 -r1.97 src/sys/fs/puffs/puffs_vfsops.c
cvs rdiff -u -r1.155 -r1.156 src/sys/fs/puffs/puffs_vnops.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/fs/puffs/puffs_vfsops.c
diff -u src/sys/fs/puffs/puffs_vfsops.c:1.96 src/sys/fs/puffs/puffs_vfsops.c:1.97
--- src/sys/fs/puffs/puffs_vfsops.c:1.96 Sun Jun 12 03:35:54 2011
+++ src/sys/fs/puffs/puffs_vfsops.c Wed Sep 21 15:36:33 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: puffs_vfsops.c,v 1.96 2011/06/12 03:35:54 rmind Exp $ */
+/* $NetBSD: puffs_vfsops.c,v 1.97 2011/09/21 15:36:33 manu Exp $ */
/*
* Copyright (c) 2005, 2006 Antti Kantee. All Rights Reserved.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: puffs_vfsops.c,v 1.96 2011/06/12 03:35:54 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: puffs_vfsops.c,v 1.97 2011/09/21 15:36:33 manu Exp $");
#include <sys/param.h>
#include <sys/mount.h>
@@ -513,9 +513,10 @@
{
struct puffs_node *pn;
struct vnode *vp, *mvp;
- int error, rv;
+ int error, rv, fsyncwait;
error = 0;
+ fsyncwait = (waitfor == MNT_WAIT) ? FSYNC_WAIT : 0;
/* Allocate a marker vnode. */
if ((mvp = vnalloc(mp)) == NULL)
@@ -574,7 +575,7 @@
pn->pn_stat |= PNODE_FAF;
mutex_exit(vp->v_interlock);
}
- rv = VOP_FSYNC(vp, cred, waitfor, 0, 0);
+ rv = VOP_FSYNC(vp, cred, fsyncwait, 0, 0);
if (waitfor == MNT_LAZY) {
mutex_enter(vp->v_interlock);
pn->pn_stat &= ~PNODE_FAF;
Index: src/sys/fs/puffs/puffs_vnops.c
diff -u src/sys/fs/puffs/puffs_vnops.c:1.155 src/sys/fs/puffs/puffs_vnops.c:1.156
--- src/sys/fs/puffs/puffs_vnops.c:1.155 Mon Aug 29 04:12:45 2011
+++ src/sys/fs/puffs/puffs_vnops.c Wed Sep 21 15:36:33 2011
@@ -1,4 +1,4 @@
-/* $NetBSD: puffs_vnops.c,v 1.155 2011/08/29 04:12:45 manu Exp $ */
+/* $NetBSD: puffs_vnops.c,v 1.156 2011/09/21 15:36:33 manu Exp $ */
/*
* Copyright (c) 2005, 2006, 2007 Antti Kantee. All Rights Reserved.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.155 2011/08/29 04:12:45 manu Exp $");
+__KERNEL_RCSID(0, "$NetBSD: puffs_vnops.c,v 1.156 2011/09/21 15:36:33 manu Exp $");
#include <sys/param.h>
#include <sys/buf.h>
@@ -50,6 +50,8 @@
#include <miscfs/genfs/genfs.h>
#include <miscfs/specfs/specdev.h>
+extern struct lwp *updateproc;
+
int puffs_vnop_lookup(void *);
int puffs_vnop_create(void *);
int puffs_vnop_access(void *);
@@ -1357,7 +1359,21 @@
struct puffs_mount *pmp = MPTOPUFFSMP(vp->v_mount);
int error, dofaf;
- mutex_enter(&pn->pn_sizemtx);
+ /*
+ * Make sure ioflush does not get stuck in low
+ * memory conditions: it should not wait for the
+ * mutex.
+ */
+ if (curlwp == updateproc)
+ KASSERT((ap->a_flags & FSYNC_WAIT) == 0);
+
+ if (ap->a_flags & FSYNC_WAIT) {
+ mutex_enter(&pn->pn_sizemtx);
+ } else {
+ if (mutex_tryenter(&pn->pn_sizemtx) == 0)
+ return EDEADLK;
+ }
+
error = flushvncache(vp, ap->a_offlo, ap->a_offhi,
(ap->a_flags & FSYNC_WAIT) == FSYNC_WAIT);
if (error)
@@ -2211,12 +2227,13 @@
struct buf *bp;
size_t argsize;
size_t tomove, moved;
- int error, dofaf, dobiodone;
+ int error, dofaf, cansleep, dobiodone;
pmp = MPTOPUFFSMP(vp->v_mount);
bp = ap->a_bp;
error = 0;
dofaf = 0;
+ cansleep = 0;
pn = VPTOPP(vp);
park_rw = NULL; /* explicit */
dobiodone = 1;
@@ -2264,8 +2281,9 @@
/* allocate transport structure */
tomove = PUFFS_TOMOVE(bp->b_bcount, pmp);
argsize = sizeof(struct puffs_vnmsg_rw);
+ cansleep = (dofaf || (curlwp == updateproc)) ? 0 : 1;
error = puffs_msgmem_alloc(argsize + tomove, &park_rw,
- (void *)&rw_msg, dofaf ? 0 : 1);
+ (void *)&rw_msg, cansleep);
if (error)
goto out;
RWARGS(rw_msg, 0, tomove, bp->b_blkno << DEV_BSHIFT, FSCRED);
